Abstract
An X-ray absorption spectroscopic study was made of seven different manganese co-ordination compounds, six of which are dinuclear and contain the structural bis(μ-oxo) unit. In all the compounds each manganese is ligated by one crown ether Schiff-base moiety. Alkali- or alkaline-earth-metal cations were introduced into this crown ether moiety in dinuclear complexes, bringing the cations (Na+, K+, Ca2+ and Ba2+) into the vicinity (<4 Å) of the manganese. The position of the X-ray absorption edge follows the order expected for the different oxidation states of manganese: 6551.6 eV for a manganese(III) monomer, 6552.1 eV for a MnIIIMnIV(μ-O)2 dimer and 6553.5 eV for a manganese(IV) dimer. Analysis of the extended-X-ray absorption fine structure of the compounds yielded information about the immediate ligation to manganese. The first shell consists of light atoms (O/N) and is composed of two sub-shells, with average distances of 1.9 Å and 2.3 Å from the Mn. The dinuclear compounds clearly show the characteristic 2.7 Å Mn-Mn distance. In the cation-containing compounds a manganese-metal distance of approximately 3.6 Å is found. The introduction of Ba2+ in the crown ether moiety induces substantial changes in the ligation pattern of the light elements. The properties of the compounds provide a model for discussion of the properties of the photosynthetic manganese complex, and the role and position of the Ca2+ cofactor.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 4075-4082 |
| Number of pages | 8 |
| Journal | Journal of the Chemical Society - Dalton Transactions |
| Issue number | 21 |
| State | Published - Nov 7 1997 |
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ASJC Scopus subject areas
- Inorganic Chemistry
Cite this
An extended X-ray absorption fine structure study of bis(μ-oxo) bridged dinuclear manganese co-ordination compounds containing alkali- and alkaline-earth-metal cations in a crown ether moiety. / Turconi, Sandra; Horwitz, Colin P.; Ciringh, Yangzhen; Weintraub, Susan E; Warden, Joseph T.; Nugent, Jonathan H A; Evans, Michael C W.
In: Journal of the Chemical Society - Dalton Transactions, No. 21, 07.11.1997, p. 4075-4082.Research output: Contribution to journal › Article
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TY - JOUR
T1 - An extended X-ray absorption fine structure study of bis(μ-oxo) bridged dinuclear manganese co-ordination compounds containing alkali- and alkaline-earth-metal cations in a crown ether moiety
AU - Turconi, Sandra
AU - Horwitz, Colin P.
AU - Ciringh, Yangzhen
AU - Weintraub, Susan E
AU - Warden, Joseph T.
AU - Nugent, Jonathan H A
AU - Evans, Michael C W
PY - 1997/11/7
Y1 - 1997/11/7
N2 - An X-ray absorption spectroscopic study was made of seven different manganese co-ordination compounds, six of which are dinuclear and contain the structural bis(μ-oxo) unit. In all the compounds each manganese is ligated by one crown ether Schiff-base moiety. Alkali- or alkaline-earth-metal cations were introduced into this crown ether moiety in dinuclear complexes, bringing the cations (Na+, K+, Ca2+ and Ba2+) into the vicinity (<4 Å) of the manganese. The position of the X-ray absorption edge follows the order expected for the different oxidation states of manganese: 6551.6 eV for a manganese(III) monomer, 6552.1 eV for a MnIIIMnIV(μ-O)2 dimer and 6553.5 eV for a manganese(IV) dimer. Analysis of the extended-X-ray absorption fine structure of the compounds yielded information about the immediate ligation to manganese. The first shell consists of light atoms (O/N) and is composed of two sub-shells, with average distances of 1.9 Å and 2.3 Å from the Mn. The dinuclear compounds clearly show the characteristic 2.7 Å Mn-Mn distance. In the cation-containing compounds a manganese-metal distance of approximately 3.6 Å is found. The introduction of Ba2+ in the crown ether moiety induces substantial changes in the ligation pattern of the light elements. The properties of the compounds provide a model for discussion of the properties of the photosynthetic manganese complex, and the role and position of the Ca2+ cofactor.
AB - An X-ray absorption spectroscopic study was made of seven different manganese co-ordination compounds, six of which are dinuclear and contain the structural bis(μ-oxo) unit. In all the compounds each manganese is ligated by one crown ether Schiff-base moiety. Alkali- or alkaline-earth-metal cations were introduced into this crown ether moiety in dinuclear complexes, bringing the cations (Na+, K+, Ca2+ and Ba2+) into the vicinity (<4 Å) of the manganese. The position of the X-ray absorption edge follows the order expected for the different oxidation states of manganese: 6551.6 eV for a manganese(III) monomer, 6552.1 eV for a MnIIIMnIV(μ-O)2 dimer and 6553.5 eV for a manganese(IV) dimer. Analysis of the extended-X-ray absorption fine structure of the compounds yielded information about the immediate ligation to manganese. The first shell consists of light atoms (O/N) and is composed of two sub-shells, with average distances of 1.9 Å and 2.3 Å from the Mn. The dinuclear compounds clearly show the characteristic 2.7 Å Mn-Mn distance. In the cation-containing compounds a manganese-metal distance of approximately 3.6 Å is found. The introduction of Ba2+ in the crown ether moiety induces substantial changes in the ligation pattern of the light elements. The properties of the compounds provide a model for discussion of the properties of the photosynthetic manganese complex, and the role and position of the Ca2+ cofactor.
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M3 - Article
AN - SCOPUS:33748515013
SP - 4075
EP - 4082
JO - Journal of the Chemical Society. Dalton Transactions
JF - Journal of the Chemical Society. Dalton Transactions
SN - 1472-7773
IS - 21
ER -